An important aim of ongoing research in the semiconductor industry is the reduction in the dimensions of semiconductor devices. Planar transistors such as metal oxide semiconductor field effect transistors (MOSFET), are particularly well suited for use in high-density integrated circuits. As the size of the MOSFET and other active devices decreases, the dimensions of the gate electrodes and gate dielectric layers decrease correspondingly. Tight control of the gate dielectric thickness is necessary to manufacture reduced-size, high-reliability, high-speed transistors.
Gate dielectric capacitors are commonly used in semiconductor devices. Common gate dielectric capacitors found in a semiconductor device include transistors, such as MOSFET. In order to improve gate dielectric capacitor performance, ultra-thin gate dielectric layers with a thickness below about 25 Å are coupled with large area capacitors. Large area capacitors are typically those with a capacitor area greater than 1000 Å2.
Gate dielectric thickness is an important parameter in gate dielectric capacitor performance. If the gate dielectric thickness is too thin, short-circuiting is a problem. If the gate dielectric layer is too thick, then the device speed will be too slow.
The thickness of the gate dielectric layer can be determined by measuring the capacitance of the gate dielectric capacitor. The thickness of the gate dielectric layer is related to the capacitance by the following formula:t=k/Cwherein t is the thickness of the gate dielectric layer, k is the dielectric constant of the gate dielectric layer, and C is the capacitance of the gate dielectric capacitor.
The capacitance of large area, ultra-thin gate dielectric capacitors cannot be accurately measured directly. The large area gate dielectric capacitors tend to suffer from high gate leakage through the gate. The capacitance of small area gate dielectric capacitors also cannot be directly measured with accuracy. Gate leakage does not appreciably hinder measuring the capacitance of small area gate dielectric capacitors, rather parasitic capacitance interferes with accurate gate dielectric capacitance measurements in small area gate dielectric capacitors. As the area of the gate dielectric capacitor is reduced, the proportion of the total capacitance due to the parasitic capacitance associated with the wiring structures increases.
The term gate dielectric capacitors, as used herein, is not to be limited to the specifically disclosed embodiments. Gate dielectric capacitors, as used herein, include a wide variety of electronic devices in addition to field effect transistors.
The term semiconductor devices, as used herein, is not limited to the specifically disclosed embodiments. Semiconductor devices as used herein, include a wide variety of electronic devices including flip chips, flip chip/package assembly, transistors, capacitors, microprocessors, random access memories, etc. in general, semiconductor devices refer to any electrical device comprising semiconductors.